1. Field of the Invention
The present invention relates to the real time monitoring of a patient's blood pressure and in particular to the taking of continuous automatic blood pressure readings.
2. Description of the Related Art
In working with a large number of different automatic blood pressure reading systems, it has been recognized that the deployment of the blood pressure cuff must be carefully considered in order to achieve accuracy in the blood pressure readings taken. It has been observed, for example, that the width of the blood pressure cuff (taken in the direction along the length of the patient's arm) must be maintained within certain ranges in order to prevent erroneous blood pressure readings.
Most of the blood pressure cuffs in use today take the form of a double-ended, elongated strip which is wrapped about as patient's limb with ends of the blood pressure cuff partly overlapping. As a minimal requirement, the amount of overlap must be sufficient to allow proper self-attachment of the strip ends so as to free an operator to perform other tasks, such as operating monitoring equipment. Recently, attention has been paid to the amount of overlap of the blood pressure cuff ends, with the appreciation that errors in overwrap, either too large or too small, even if satisfactory to allow blood pressure readings to be taken, result in an unwanted shift of those readings.
In addition to variations encountered in applying a blood pressure cuff to a patient's limb, a variation of blood pressure readings also arises from the fact that, as a practical matter, there are a relatively large number of different size cuffs by manufacturers of blood pressure reading equipment. For example, systems having nine or more differently sized blood pressure cuffs are not uncommon. Cuff sizes typically include a smallest size blood pressure cuff for neonatal patients and a largest blood pressure cuff size for adult thigh readings. Some blood pressure reading equipment requires the user to specify the cuff size by a special purpose input, such as a special, identifying switch or some other pre-defined selection means. Other systems require that special pneumatic fittings be employed to provide a self-identification of the size of the blood pressure cuff with which the fitting is associated. Accordingly, some type of keying system between the blood pressure cuff and the associated pneumatic circuitry is employed. The complexities in taking blood pressure readings is growing at a time when increasing demands are being made on care givers and other personnel charged with the responsibility of taking blood pressure readings. The need for an improved, automatic blood pressure reading system still exists.